1. Field of the Invention
The present invention relates to an electronic clock and a pointer position detecting method, or more specifically to an electronic clock and a pointer position detecting method for obtaining a signal for making a specific action by detecting that a pointer has come to predetermined position.
2. Description of the prior Art
An electronic clock is arranged so as to make a specific action when a pointer comes to predetermined position. Examples of the specific action include sounding time, turning a calendar, adjusting the clock based on radio wave received from the outside, and so on. When time is to be sounded when a minute hand stands at twelve o""clock, the electronic clock outputs a time sounding signal to a circuit for sounding the time by detecting that the minute hand stands at twelve o""clock. That is, the position of the pointer must be detected in the electronic clock to make a specific action when the pointer comes to predetermined position.
As a prior art, there has been known a technology of detecting the pointer position by using a mechanical contact. In the technology of using the mechanical contact, a center wheel and pinion is provided with a projecting cam and a contact made of leaf spring facing to the center wheel and pinion. Because the contact is hooked by the cam every time when the center wheel and pinion makes a turn in a hour and oscillates between a pair of contact springs, it is judged that the minute hand has come to predetermined position (position indicating twelve o""clock for example) when the contact is hooked by the cam and a signal, e.g., a time sounding signal, for making a predetermined action is outputted.
Japanese Patent Laid-Open NoS. 55-82080 and 61-118483 and Japanese Utility Model Laid-Open No. 56-10883 have also disclosed technologies of optically detecting the pointer position. According to the technologies, gears in a wheel train is disposed so that at least a part thereof overlap each other, each gear is provided with a transparency which agrees at constant cycle, e.g., once in a hour, and a light emitting device and a light receiving device are disposed on an extension in the axial direction at the position where the respective transparencies agree. The respective transparencies agree when the light receiving device receives light from the light emitting device. Then, the clock judges that the pointer has come to predetermined position, e.g., position indicating twelve o""clock, and outputs a signal, e.g., a time sounding signal, for making a predetermined operation.
However, the method of detecting the pointer position by using the mechanical contact has had a problem that the precision of detection drops due to deterioration of the contact and the contact springs. It also has had a problem that torque of a motor must be increased because the contact becomes a rotational resistance of the wheel train, thus increasing power consumption.
Meanwhile, the method of optically detecting the pointer position has had problems that it is costly because it requires the light emitting device and the light receiving device and that it is difficult to compact the clock. It also has had a problem that its structure is complicated because the light emitting device and the light receiving device must be disposed within a narrow space. It has had another problem that its power consumption increases to operate the light emitting device and the light receiving device.
The present invention has been devised in view of the problems described above and its object is to provide an electronic clock and a pointer position detecting method for detecting the pointer position accurately without adding individual electric device.
In order to achieve the above-mentioned object, an inventive electronic clock comprises reference signal generating means for generating a reference signal; pulse control means for outputting a plurality of pulse signals whose strength is different based on the reference signal to a motor to drive the motor; a wheel train which is rotated by the motor; indicator means which is rotated by the wheel train; position detecting means for detecting predetermined position of the indicator means; and rotation judging means for outputting a rotation signal or a non-rotation signal by detecting whether or not the motor rotates. It is also provided with high load means for applying high load to the wheel train at constant cycle to rotate the motor only when the high load is applied to the wheel train and a pulse signal of predetermined strength or more is outputted to the motor; the pulse control means outputs a normal driving pulse, outputting a first auxiliary driving pulse whose strength is greater than that of the normal driving pulse when the rotation judging means outputs a non-rotation signal after outputting the normal driving pulse or outputting a second auxiliary driving pulse whose strength is greater than the first auxiliary driving pulse and the predetermined strength when the rotation judging means outputs the non-rotation signal after outputting the first auxiliary driving pulse; and the position detecting means judges that the indicator means is located at the predetermined position when the second auxiliary driving pulse is outputted.
An inventive pointer position detecting method for detecting that indicator means has come to predetermined position, comprises steps of: applying high load to a wheel train for rotating the indicator means at constant cycle so that a motor rotates only when the high load is applied and a pulse signal of predetermined strength or more is outputted to the motor for rotating the wheel train; judging whether or not the motor rotates by outputting a normal driving pulse to the motor; judging whether or not the motor rotates by outputting a first auxiliary driving pulse whose strength is greater than that of the normal driving pulse to the motor when the motor does not rotate by the normal driving pulse; outputting a second auxiliary driving pulse whose strength is greater than the first auxiliary driving pulse and the predetermined strength to the motor when the motor does not rotate by the first auxiliary driving pulse; and judging that the indicator means is located at the predetermined position when the second auxiliary driving pulse is outputted.
Japanese Patent Publication Nos. 63-18148, 63-18149 and 57-18440 have disclosed the technology of detecting that a motor rotates by outputting a relatively weak normal driving pulse to the motor for rotating a wheel train and of always rotating the motor by outputting a relatively strong auxiliary driving pulse when the motor does not rotate by the normal driving pulse. Normally, power consumption of a motor may be reduced by rotating by the normal driving pulse which consumes less power and by using the auxiliary driving pulse whose power consumption is large only when load is applied to the motor by some reason.
Then, the present invention is arranged so that high load is applied to the wheel train when the indicator means comes to predetermined position and the motor rotates only when the high load is applied and a pulse signal of predetermined strength or more is outputted to the motor. While the motor normally rotates by the normal driving pulse or a first auxiliary driving pulse, it does not rotate when high load is applied to the wheel train, so that it is rotated by applying a stronger second auxiliary driving pulse. Accordingly, it becomes possible to detect the predetermined position of the indicator means by the second auxiliary driving pulse because the second auxiliary driving pulse is outputted when the indicator means is located at the predetermined position. Still more, no light receiving device like those in the prior art is required.
For instance, when it is arranged so that high load is applied to the wheel train when the minute hand stands at twelve o""clock, the second auxiliary driving pulse for rotating the motor when the minute hand stands at twelve o""clock is required. Accordingly, the minute hand stands at twelve o""clock when the second auxiliary driving pulse is outputted.
In the electronic clock described above, the inventive electronic clock is characterized in that the position detecting means judges that the indicator means has come to the predetermined position when the rotation judging means outputs the non-rotation signal after outputting the first auxiliary driving pulse.
In the pointer position detecting method, the inventive pointer position detecting method is characterized in that the indicator means is judged to be located at the predetermined position when the motor does not rotate by the first auxiliary driving pulse.
That is, according to the invention, it is judged that the indicator means has come to the predetermined position when the motor does not rotate by the first auxiliary driving pulse. It is noted that the motor does not rotate by the first auxiliary driving pulse when the high load is applied to the wheel train. Accordingly, it means that the high load is applied to the wheel train, i.e., the indicator means is located at the predetermined position, when the motor does not rotate by the first auxiliary driving pulse. Therefore, it becomes possible to detect the pointer position by utilizing the structure necessary for operating the electronic clock.
In the electronic clock described above, the inventive electronic clock further comprises number-of-revolutions counting means for counting a number of revolutions of the motor since when the pulse control means has outputted the second auxiliary driving pulse for the first time; and number-of-revolutions judging means for outputting a control signal for outputting the second auxiliary driving pulse when the number of revolutions reaches to the number of revolutions corresponding to the cycle in which the high load is applied to the wheel train to the pulse control means.
In the pointer position detecting method described above, the inventive pointer position detecting method is characterized in that a number of revolutions of the motor is counted and the second auxiliary driving pulse is outputted when the number of revolutions reaches to a number of revolutions corresponding to the cycle in which high load is applied to the wheel train.
That is, according to the invention, the number of revolutions of the motor is counted from when the second auxiliary driving pulse is started to be outputted and when the number of revolutions reaches to the number of revolutions corresponding to the cycle in which the high load is applied to the wheel train, the second auxiliary driving pulse is outputted without outputting the normal driving pulse and the first auxiliary driving pulse. It is possible to predict when high load is applied next by counting the number of revolutions of the motor from when the second auxiliary driving pulse is outputted for the first time because the high load is applied to the wheel train at constant cycle. Accordingly, it becomes possible to output the second auxiliary driving pulse directly when the high load is predicted to be applied. As a result, it becomes possible to save power consumption required for outputting the normal driving pulse and the first auxiliary driving pulse.
For instance, when it is arranged so that high load is applied to the wheel train when the minute hand stands at twelve o""clock, the high load is applied again to the wheel train after when the motor rotates by 3600 times since when the high load has been applied to the wheel train for the first time when the motor rotates once in a second. Accordingly, it is apparent that the motor does not rotate unless the second auxiliary driving pulse is outputted when the number of revolutions of the motor reaches to 3600 since when the high load is applied to the wheel train for the first time. In this case, the second auxiliary driving pulse is outputted directly without outputting the normal driving pulse nor first auxiliary driving pulse to save the power consumption for outputting the normal driving pulse and first auxiliary driving pulse.
In the electronic clock described above, the inventive electronic clock further comprises pulse output times counting means for counting a number of output times of the second auxiliary driving pulse during when the number of revolutions of the motor reaches to the number-of-revolutions signal corresponding to the cycle in which the high load is applied to the wheel train; and pulse number judging means for outputting a control signal for stopping to generate the pulse signal to the pulse control means when the output times of the second auxiliary driving pulse exceeds a predetermined number of times.
In the pointer position detecting method described above, the pointer position detecting method is characterized in that a number of output times of the second auxiliary driving pulse is counted during when the number of revolutions of the motor reaches to the number of revolutions corresponding to the cycle in which the high load is applied to the wheel train to stop to generate the pulse signal when the number of output times exceeds a predetermined number of times.
That is, according to the invention, the number of revolutions of the motor is counted since when the second auxiliary driving pulse has been outputted for the first time and the number of output times of the second auxiliary driving pulse is counted until when the number of revolutions reaches to the number of revolutions corresponding to the cycle in which the high load is applied to the wheel train. When the number output times of the second auxiliary driving pulse exceeds a predetermined number of times, unpredictable high load is applied to the wheel train by some reason, i.e., the clock is defective. Then, it becomes possible to save power and to inform of the trouble of the clock to its user by stopping the operation of the clock by stopping the generation of the pulse signal.
For instance, when high load is to be applied to the wheel train when the minute hand stands at twelve o""clock, the high load is normally applied to the wheel train only once in an hour. When the high load is applied to the wheel train more than once in an hour here, i.e. when the number of output times of the second auxiliary driving pulse becomes 2, it can be seen that the clock is defective because there exists high load which has not been predicted in the design thereof. In such a case, it is possible to save power and to inform of the trouble of the clock to its user by stopping the operation of the clock by stopping to generate the pulse signal.
In the electronic clock described above, the inventive electronic clock further comprises pulse output times counting means for counting a number of output times of the second auxiliary driving pulse during when the number of revolutions of the motor reaches to the number-of-revolutions signal corresponding to the cycle in which the high load is applied to the wheel train; and pulse number judging means for outputting a control signal for changing output intervals of the pulse signal to the pulse control means when the output times of the second auxiliary driving pulse exceeds a predetermined number of times.
In the pointer position detecting method described above, the inventive pointer position detecting method is characterized in that a number of output times of the second auxiliary driving pulse is counted during when the number of revolutions of the motor reaches to the number of revolutions corresponding to the cycle in which the high load is applied to the wheel train to change output intervals of the pulse signal when the number of output times exceeds a predetermined number of times.
That is, according to the present invention, the number of revolutions of the motor is counted since when the second auxiliary driving pulse has been outputted for the first time and the number of output times of the second auxiliary driving pulses which are outputted during when the number of revolutions reaches to the number of revolutions corresponding to the cycle in which the high load is applied to the wheel train is counted. It is noted that when the number of output times of the second auxiliary driving pulses exceeds a predetermined number of times, unpredictable high load is applied to the wheel train by some reason, i.e., the clock is defective. Then, the pointer of the clock is caused to make abnormal operations by changing the output intervals of the pulse signal. Thereby, it is possible to inform the trouble of the clock.
For instance, when high load is to be applied to the wheel train when the minute hand stands at twelve o""clock, the high load is applied to the wheel train only once in an hour. When high load is applied to the wheel train more than once in an hour, i.e., when the number of output times of the second auxiliary driving pulse becomes 2, it can be seen that the clock is defective. In this case, the trouble of the clock is informed to its user by moving a second hand which normally moves at intervals of one second at intervals of five seconds by changing the intervals of the pulse signals.
An inventive electronic clock comprises reference signal generating means for generating a reference signal; pulse control means for outputting a plurality of pulse signals whose strength is different based on the reference signal to a motor to drive the motor; a wheel train which is rotated by the motor; indicator means which is rotated by the wheel,train; position detecting means for detecting predetermined position of the indicator means; and rotation judging means for outputting a rotation signal or a non-rotation signal by detecting whether or not the motor rotates. The electronic clock is also characterized in that it is provided with high load means for applying high load to the wheel train continuously by a plurality of times at constant cycle so that the motor rotates only when the high load is applied to the wheel train and a pulse signal of predetermined strength or more is outputted to the motor continuously by a plurality of times; the pulse control means outputs a normal driving pulse, outputting a first auxiliary driving pulse whose strength is greater than that of the normal driving pulse when the rotation judging means outputs a non-rotation signal after outputting the normal driving pulse or outputting a second auxiliary driving pulse whose strength is greater than the first auxiliary driving pulse and the predetermined strength when the rotation judging means outputs the non-rotation signal after outputting the first auxiliary driving pulse; and the position detecting means judges that the indicator means is located at the predetermined position when the second auxiliary driving pulse is outputted continuously by a plurality of times and when the rotation judging means outputs the rotation signal as the normal driving pulse or first auxiliary driving pulse is outputted after that.
In the pointer position detecting method for detecting that indicator means has come to predetermined position, the inventive pointer position detecting method comprises steps of applying high load to a wheel train for rotating the indicator means continuously by a plurality of times at constant cycle so that a motor rotates only when the high load is applied and a pulse signal of predetermined strength or more is outputted to the motor for rotating the wheel train; judging whether or not the motor rotates by outputting a normal driving pulse to the motor; judging whether or not the motor rotates by outputting a first auxiliary driving pulse whose strength is greater than that of the normal driving pulse to the motor when the motor does not rotate by the normal driving pulse; outputting a second auxiliary driving pulse whose strength is greater than the first auxiliary driving pulse and the predetermined strength to the motor when the motor does not rotate by the first auxiliary driving pulse; and judging that the indicator means is located at the predetermined position when the second auxiliary driving pulse is outputted continuously by a plurality of times and the motor rotates when the normal driving pulse or first auxiliary driving pulse is outputted after that.
That is, according to the invention, the plurality of high loads is applied continuously to the wheel train before the indicator means comes to the predetermined position and the motor rotates only when the high load is applied and pulse signals of predetermined strength or more are outputted continuously by a plurality of times. The indicator means is judged to be located at the predetermined position when the second auxiliary driving pulse is outputted continuously by a plurality of times and then the motor rotates by the normal driving pulse or the first auxiliary driving pulse. Therefore, it is possible to detect the pointer position by utilizing the structure required for operating the electronic clock.
For instance, when high load is applied to the wheel train by which the motor does not rotate unless the second auxiliary driving pulses are outputted continuously by five times 5 seconds before the minute hand stands at twelve o""clock, the second auxiliary driving pulses must be outputted continuously by five times in order to rotate the motor when the high load is applied to the wheel train and the motor rotates by the normal driving pulse or the first auxiliary driving pulse after that. Accordingly, the high load is applied to the wheel train when the second auxiliary driving pulses are outputted continuously by five times and it can be seen that the minute hand stands at twelve o""clock when the motor rotates by the normal driving pulse or the first auxiliary driving pulse.